The Royal Swedish Academy of Sciences today announced that the Nobel Prize in Physics for 2016 would be awarded to Prof. David James Thouless, Prof. F. Duncan M. Haldane and Prof. J. Michael Kosterlitz ”for theoretical discoveries of topological phase transitions and topological phases of matter”. Prof. Thouless has been awarded half the prize share, while the other half will be shared equally between Prof. Haldane and Prof. Kosterlitz. The scientists have used advanced mathematical methods to explain unusual properties of matter when cooled to very low temperatures.

Prof. Thouless, Professor Emeritus at the University of Washington, Seattle is known for his work on condensed matter physics and has proposed the Kosterlitz-Thouless(KT) phase transition models, Thouless energy and topological quantum numbers for matter. Prof. Haldane is Eugene Higgins Professor of Physics at the Princeton University, USA, and has widely contributed to the field of condensed matter theory. Prof. Kosterlitz is currently Harrison E. Farnsworth Professor of Physics at Brown University, USA, and is known for his research on condensed matter theory, one and two dimensional physics, and phase transitions.

Matter is ordinarily found in three states - solid, liquid and gas. Phase transitions are changes between these states. At very low temperatures (close to absolute zero i.e. -273 degree Celsius), some substances can exhibit unusual or exotic properties that they do not display at more ordinary temperatures. For instance, some substances that do not allow electric current to pass through them at normal temperatures, suddenly cease to offer any resistance to electric current when cooled below a certain temperature.

Topology is a branch of mathematics dealing with geometrical properties that don't change when stretched or bent, but not when torn apart. For example, a donut and a coffee mug have the same topology. By stretching and bending a donut, without tearing it apart, one can turn it into a coffee mug shape. The BKT theory found that insights from this branch of mathematics are essential to understand the phase transitions of materials at low temperatures. Using topological ideas has led to a lot of ongoing research about material properties.

The BKT (Berezinskii - Kosterlitz - Thouless) theory, proposed by two of the awardees, overturned the earlier theory that superconductivity could not occur in thin layers. The BKT theory deals with the question of how the properties of matter can be so radically transformed by mere heating or cooling, and the changes in how its constituting atoms line up to create the macroscopic effect - a phenomenon that is otherwise puzzling to classical physics. With this, they were also able to successfully demonstrate that superconductivity could occur at low temperatures and explain the mechanism, phase transition, that makes superconductivity disappear at higher temperatures.

Prof. Haldane discovered the first example of a new type of topological material, which is now a hot field of research in condensed matter physics. In the theoretical studies of chains of magnetic atoms that occur in some materials, he discovered how topological concepts can be used to understand the properties of chains of small magnets found in some materials.

“Thanks to their pioneering work, the hunt is now on for new and exotic phases of matter. Many people are hopeful of future applications in both materials science and electronics”, stated a press release from the Royal Swedish Academy of Science on this year’s Physics Nobel Prize.